If you take the time to notice, you will find that you pretty well have non stop thoughts going on in your head. A small number of them are useful; the vast majority are repetitive and some of them make you feel bad, limit you or seriously distort your experience. When you really look at it, thoughts run your life.
How is this possible? It is simply because you mistakenly assume two things:
Neither is remotely true.
Thoughts appear to YOU. They are not who you are. YOU are the one noticing the thoughts. This discovery in itself can set you FREE.
Whilst some thoughts are useful and are true (e.g. I need to get up for work) many thoughts are the result of past conditioning and experiences and are imaginary (e.g. I am not good enough).
What to do? Start to become an observer of the thinking process. As you learn to separate yourself from your thinking, you will start to feel calmer and you will find that you are a lot more spacious and have a lot more choice than you ever thought possible.